LINK PROTEIN IS UBIQUITOUSLY EXPRESSED IN NON-CARTILAGINOUS TISSUES WHERE IT ENHANCES AND STABILIZES THE INTERACTION OF PROTEOGLYCANS WITH HYALURONIC-ACID
F. Binette et al., LINK PROTEIN IS UBIQUITOUSLY EXPRESSED IN NON-CARTILAGINOUS TISSUES WHERE IT ENHANCES AND STABILIZES THE INTERACTION OF PROTEOGLYCANS WITH HYALURONIC-ACID, The Journal of biological chemistry, 269(29), 1994, pp. 19116-19122
Link protein (LP) is an abundant protein of cartilage which stabilizes
the interaction of aggrecan with hyaluronic acid (HA). In this study
we report that LP is also present in a large number of embryonic non c
artilaginous tissues. We demonstrate, using RNase protection experimen
ts, that the coding region of the LP mRNAs isolated from these tissues
is identical to that present in cartilage. Furthermore, we show that
the LP mRNAs are translated in non-cartilaginous tissues by the identi
fication of LP polypeptides with monoclonal antibody 4B6/A5 in Western
blots. LP is localized in the extracellular matrix of the mesoderm al
ong the entire digestive tract and in the dermis of the embryonic skin
as revealed by immunofluorescence analysis. Investigations on the int
eractions between LP and proteoglycans from skin and proventriculus de
monstrate that LP can enhance the binding of proteoglycans from these
tissues to HA. In addition, we find that the same proteoglycans bound
to HA in the presence of LP are always more resistant to competition b
y soluble HA than in the absence of LP. Our results suggest that LP is
involved in the stabilization of extracellular matrices of a wide var
iety of non-cartilaginous tissues.